Substance use and substance use disorders (SUD) are among of the most critical public health concerns in the United States. Because patients with substance use and SUD are encountered most frequently in non-specialty, general medical settings, there is a great need to develop a diverse and interdisciplinary pool of clinician- scientists to conduct high-quality impactful research on substance use and SUD in these settings. Therefore, we propose the University of Pittsburgh Collaboration in Addiction Training Scholars (PittCATS) Program. PittCATS leverages the exceptional cadre of multidisciplinary substance use and SUD investigators and mentors, existing postdoctoral training programs in substance use and SUD, and the exceptional career development experience and resources of the University of Pittsburgh's Institute for Clinical Research Education (ICRE) and the Clinical and Translational Science Institute to achieve its goal of preparing highly qualified junior faculty Scholars for independent careers in substance use and SUD research, with a focus on the care of patients with substance use and SUD in general medical settings. The junior faculty Scholars will be supported for 3-5 years and required to have a MD, PhD in a clinical discipline, PharmD, or equivalent. The Program's short-term objectives are to: 1) recruit outstanding Scholars with strong motivation to conduct interdisciplinary substance use and SUD research; 2) help Scholars develop a rigorous customized career development plan; 3) provide Scholars with hands-on interdisciplinary mentored experiences in the conduct of clinical research from conceptualization to completion, presentation, and publication and dissemination of results; and 4) ensure close, effective mentoring of Scholars to guide their research career development. The long-term objectives are: 1) provide Scholars the tools to develop and submit competitive grant applications for independent funding; and 2) teach Scholars the leadership and professional skills necessary to excel as clinical researchers, mentors, and leaders in substance use and SUD research. To achieve these objectives, Scholars develop a customized career development plan and engage in a comprehensive set of training activities: 1) rigorous coursework in research methodology; 2) substance use and SUD research and topical seminars; 3) mentored research projects; 4) development of an independent research grant proposal; 5) mentoring training; 6) leadership and professionalism training; and 7) responsible conduct of research training. The success of the Program will be measured by course, Program, and mentor-mentee evaluations and through short and long- term tracking of career outcomes, including acquisition of research competencies, independent grant funding, presentations, peer-reviewed papers, promotion, and awards. The Program is administered by a Program Director, two Program Co-Directors, an Executive Committee, and an Advisory Committee who together comprise extensive experience and accomplishments in substance use and SUD research, mentoring, training, and career development across multiple disciplines.